Nutrition 2

Anabolism:

Building of molecules

Catabolism:

Breakdown of molecules

Parts of the cell:

Coenzymes:

Compounds that help an enzyme

Usually vitamins or minerals

Describe the 3 pathways involved in the breakdown of glucose:

1. Glycolysis - phosphates are added to glucose. The molecules rearrange and split in half. Only, pyruvate. A little ATP is made, but not enough to live on.

2. Kreb’s cycle - begins with pyruvate then joins with Coenzyme-A to make Acetyl-coA, which joins with oxaloacetic acid to form citric acid, then several reactions occur forming 4 products (oxyloacetic acid, CO2, NADH, and FADH2). A few ATP is made but not enough to live

3. Electron Transport System - begins with NADH and FADH2 which splits releasing hydrogens and electrons which flow through proteins across membranes releasing energy, which is used to make ATP. Hydrogens and electrons join with oxygen to form water

Cori cycle:

When there is a deficiency of oxygen causes pyruvate to be converted into lactic acid which causes muscle pain and fatigue

When the muscle relaxes, blood circulates through the fibers and carries the lactic acid to the liver. The liver converts the lactic acid back into glucose

Fat metabolism

Glycerol is converted to pyruvate which enters Kreb’s cycle

Beta oxidation occurs

Fatty acids are broken into 2 carbon fragments by beta oxidation and the fragments enter the Kreb’s cycle

Deamination:

The removal of amine to form ammonia and a 2 fragment that enters the Kreb’s cycle

Transamination

Transferring the amine group to another compound then the leftover fragment enters the Kreb’s cycle

Production of ketones:

Carbohydrate deficiency causes oxyloacetic acid to be converted into glucose for the brain

Then fats and proteins are broken down to carbon fragments but then have nothing to join in the Kreb’s cycle so they travel to the liver and the liver converts to ketones to be flushed out in the urine

Alcohol:

Drinking alcohol is called ethanol

CH3CH2OH

It penetrates cell membranes and damages organelles

Alcohol is not digested

Proof:

Percentage of alcohol in a drink

Half the proof number = the percentage

200 proof = 100% alcohol

Absorption and metabolism of alcohol and its effects on the liver:

About 20% is absorbed through the walls off the stomach then alcohol dehydrogenase breaks down some of the remaining 80%

What isn’t broken down enters the intestine and is absorbed and travels through the liver. In the liver, it ties up enzymes that also break down fats, so fatty acids accumulate in the liver

Fasting for even one day causes the liver not to make alcohol dehydrogenase to conserve and make other things, so drinking after not eating is worse

This causes the liver to be unable to activate vitamin D or make bile and causes drugs to last longer

Breakdown produces Acetaldehyde and hydrogen ions which kill cells and denature proteins

The vitamin Niacin then picks up the hydrogen ion which causes a deficiency of niacin in the rest of the body and Acetaldehyde destroys vitamin B6

The liver cells die and become scar tissue (fibrosis) and is reversible

Continued exposure to alcohol causes cirrhosis which is hardening of the liver and is irreversible

Some cells can regenerate and produce more liver causing and even bigger liver (enlarged stomach)

Walking and coughing will not help, sleep it off

Explain the reason behind breathalyzer or urine analysis for drunkenness:

10% of alcohol leaves the body through the breath and urine

That amount is directly proportional to the amount in the blood

The amount in the blood is directly proportional to drunkenness

Effects of alcohol on the brain:

It is a narcotic and depressant

First it depresses the frontal lobe, which controls judgement, reasoning so it seems to be a stimulant

Second, inhibits vision and speech centers

Third, disturbs cerebellum of voluntary muscles

Fourth, affects the brain stem depressing the breathing and heart rates

Persons usually pass out first which is beneficial because depressed brain stem causes death

Also depresses production of ADH, which makes the person more thirsty, urine, and causes the person to drink more alcohol

It is possible to drink so fast you die before passing out

Effects of alcohol on the digestive tract:

Causes stomach to over secrete acid and histamine which irritates the lining causing ulcers and inflammation on other parts of the body

Also causes intestinal cells to stop absorbing B vitamins and causes folate to be released by intestinal cells instead of absorbing it

Long term effects of alcohol:

Affects rods in the eye to process the alcohol instead of vitamin A

Directly toxic to cardiac and skeletal muscle causing deterioration

Increases BP, causes cancer of mouth, throat, esophagus, and lungs

Slows the immune system and production of antibodies

Slows the metabolism of medicines so they can build up and kill

Number of calories in a pound of fat:

3,500 calories

Hunger:

Physiologic need for food

The hypothalamus controls much concerning hunger based on nutrients in the blood, exercise, hormones, sights, smells, climate, and temp.

People override the hypothalamic signals for various reasons

Appetite:

Desire for food

Amylin:

Slows stomach and promotes satiety (full)

Cholecystokinin:

Causes the brain to feel full

Enterostatin:

Causes the brian to reduce fat intake

Ghrelin:

Stimulates hunger and food intake

Glucagon-like peptide 1:

Slows the stomach and reduces appetite

Oxyntomodulin:

Suppresses appetite

Peptide YY:

Reduces appetite and slows the stomach

Proteins:

Made of amino acids

Main functions are fibers, antibodies, hormones, receptors, and channels

Structures are primary

Structure of amino acid:

Used to make neurotransmitters, melanin, thyroxine, and niacin

20 most common amino acids found in humans:

Histidine

Isoleucine

Leucine

Lysine

Methionine

Phenylalanine

Threonine

Tryptophan

Alanine

Arginine

Asparagine

Aspartic acid

Cysteine

Glutamic acid

Glutamine

Glycine

Proline

Serine

9 essential amino acids:

Histidine

Isoleucine

Leucine

Lysine

Methionine

Phenylalanine

Threonine

Tryptophan

Valine

Conditionally essential amino acids:

Require other amino acids in order to be made by the body

Arginine

Asparagine

Glutamine

Glycine

Proline

Serine

Tyrosine

Peptide bond:

Link between the acid group of one amino acid and the amine group of another amino acid

Dipeptide:

Two amino acids joined together

Tripeptide:

3 amino acids joined together

Oligopeptide:

4 - 10 amino acids joined together

Polypeptide:

11 or more amino acids joined together

Chemistry behind protein folding:

Proteins fold so that the hydrophilic groups are on the outside and hydrophobic groups are on the inside

Then the shape and fold are maintained by amino acid interactions like hydrogen bonding and disulfide bridges

Denaturation:

Disruption of a protein’s 3-D shape

Protein digestion and absorption:

Denatured in the stomach by HCl

Then pepsin breaks them down to medium sized pieces

Then enzyme proteases breaks them down into short pieces

Fallacies about protein digestion:

Amino acid supplements are better than whole proteins

If you are lacking an enzyme, just eat it

Protein supplements build muscle

Acid:

Compound that releases hydrogen ions

Proton donor

Base:

Compound that joins a hydrogen ion

Proton acceptor

pH:

Logarithmic measure of the amount of hydrogen ions

Buffer:

Compound that helps maintain a stable pH

Chemistry of protein buffer system:

Protein buffer acids and bases and acids and bases can denature proteins

The main component is any amino acid

Collagen:

Thick, strong protein fiber and connective tissue

Enzymes:

Proteins that cause reactions to occur

Antibodies:

Proteins that attach to antigens as a signal for the immune system to destroy that antigen

Antigens:

Any substance that causes an immune response

Hormones:

Compounds made by a gland released into blood stream to affect other cells

Cell membrane structure:

2 layers of lipids with proteins scattered throughout

Transferrin:

Protein that carries iron through the liver to the bone marrow

Fibrin:

Protein fibers that trap blood cells to form a clot

Opsin:

Protein that makes part of the visual molecule in the retina

Neurotransmitter:

Compound released at the end of a neuron to stimulate the next cell

Complete protein:

Contain all the essential amino acids

From animals (meats)

Incomplete protein:

Do not contain all 9 essential amino acids (vegetables)

Biological value:

Percentage of nitrogen in a protein that is absorbed or retained

PEM:

Protein Energy and Malnutrition

Usually deficiency in protein

Over 500,000,000 children have it

Marasmus:

Starvation

Kwashiokor:

Severe protein deficiency

Because they lack protein, they cannot maintain proper water balance and experience swelling

Dysentry:

Severe diarrhea

Often happens in malnutrition

Aflatoxin:

Mold that inhibits protein synthesis and causes cancer

Found in grains and nuts

Edema:

Swelling

Also happens in several nutritional deficiencies

N balance:

Amount of nitrogen consumed compared to excreted

Recommended protein intake:

10-15% of today’s calories

Problems with high protein diets and amino acid supplements:

Cause heart disease, cancer, osteoporosis, obesity, and kidney stones

Discuss nutritional genomics:

Studies of how nutrients and foods influence gene activity

Neuropeptide Y:

Stimulates the desire to eat

Decreases energy expenditure

Increases fat storage

Thermogenesis:

Generation of heat

Basal metabolism:

Energy needed to maintain life at rest

2/3 of our energy used is basal metabolism

Lean tissue is more active than fat tissue

Thermic effect of food:

The energy required to digest and metabolize food

Usually 10% of the calories

Energy output formula:

weight/2.2 × 24 x gender value (1 for men, .9 women) x activity factor

Calculate the daily energy need of a 10 yr old boy who weighs 66 lbs and sits at school at day and watches TV all night:

66/2.2 × 24 × 1 × 1.3 = 936 calories

Frame size:

The size of a person’s bone and muscles

Body mass index:

weight in kg/ height in m²

Underweight = less than 20

Normal = 20-25

Overweight = 25+

Calculate the body mass index of a man who weighs 220 lbs and is 5’10 and determine if he is at a health risk:

31.6

Overweight

Describe some problems with being overweight:

Diabetes

High BP

Heart disease

Sleep apnea

Disabilities

Infertility

Complications in surgery

What is the minimum recommended body fat percentage?

5% for men

15% for women

Problems with being underweight:

Infertility

Fatigue

Poor concentration and memory

Poor immune system

Anorexia Nervosa:

Self starvation

Consequences: anemia, dry skin, diarrhea, heart failure, insomnia

Bulimia:

Vomiting or using laxatives to loose weight

Consequences: poor immune system, fluid and mineral imbalances, kidney and heart failure

Calculate the energy need of a college female weighing 121 lbs and doing child care every evening:

121/2.2 × 24 x .9 × 1.5 = 1186 calories

Characteristics of fat cells:

Relationship between lipoprotein lipase and weight gain or loss:

Prader Willi syndrome:

White fat and brown fat:

Causes of overweight and obesity:

Issues concerning weight loss:

Cellulite:

Bariatrics:

Sibutramine, meridia:

Orlistat:

Phentermine, diethylpropion:

Off label uses:

Gastric bypass or banding:

Liposuction:

Strategies for weight loss:

Strategies for gaining weight: